This invention relates to a centrifuge having a rotatable solid-walled drum with an inlet for the mixture to be centrifuged, which consists of liquid and solids, an overflow for the clarified liquid, and an outlet for the solids and also having a pushing means for controlling the movement of the solids in the solid-walled drum towards the outlet for the solids.
Known centrifugal clarifiers of this kind have a conical solid-walled drum, and the pushing means disposed in the latter comprises a worm which rotates at a different speed from that of the solid-walled drum. The overflow for the clarified liquid is situated at the wider end of the conical solid-walled drum. The outlet for the solid material is situated at the narrower end of the conical solid-walled drum, and is located above the level of liquid of the clarified liquid overflow.
It is a disadvantage of these known centrifugal clarifiers that the solid-walled drum and the worm must be conical, so that manufacture is made more expensive. Another more serious disadvantage of these known centrifugal clarifiers is the fact that they are suitable only for treating mixtures which have a dry substance concentration of at least 2.5% solids in the mixture. Moreover, the diameter of the solid particles must not be under 3.0 .mu..